Filter device

ABSTRACT

A filter device may include a filter housing with a filter housing pot and a cover screwable onto the filter housing pot, and an annular filter element arranged in the filter housing and having an axially protruding pin for closing a run-off channel. The annular filter element may be connected to the cover via a first thread, which may have a dome protruding centrally and axially from an upper end disc of the annular filter element, with an outer thread interrupted by free passages, and hollow cylindrical spring elements, which may protrude axially from the cover and on which an inner thread portion designed to complement the outer thread may be arranged. Each inner thread portion may extend over a longer circumferential portion than one of the free passages. The first thread may be designed running counter to a second thread arranged between the filter housing pot and the cover.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to International Patent Application No.PCT/EP2016/057600, filed on Apr. 7, 2016, and German Patent ApplicationNo. DE 10 2015 207 231.2, filed on Apr. 21, 2015, the contents of bothof which are incorporated herein by reference in their entireties.

TECHNICAL FIELD

The present invention relates to a filter device having a housing with afilter housing pot and with a cover that can be screwed onto the latter.The invention relates furthermore to an annular filter element for sucha filter device.

BACKGROUND

Generic filter devices are sufficiently and diversely known.

From DE 197 07 132 A1 a filter device having a housing with a filterhousing pot and with a cover that can be screwed onto the latter, andwith an annular filter element arranged therein is known, wherein atleast one snap-on means is provided, by means of which a detachablesnap-on connection is able to be produced between the filter element andat least one of the housing parts. Hereby it is to be made possible inparticular to mount or respectively to dismantle a filter element moresimply without, in so doing, having to come in direct contact with thefilter element.

From DE 10 2012 00 876 C5 a liquid filter of an internal combustionengine with a filter housing is known, which is connected to a liquidduct system. A housing pot is connected here to a housing cover via ahousing/cover connection, wherein this connection can be locked andunlocked by means of a housing rotational movement of the housing potrelative to the housing cover about an imaginary mounting axis. A filterelement is connected to the housing cover via an element/coverconnection. The two connections are coordinated to one another here suchthat on a rotary movement of the housing pot relative to the housingcover for opening or closing the connection there, this rotary movementis transferred to the filter element by means of the element/housingconnection, so that the filter element can be rotated jointly with thehousing pot relative to the housing cover. As the closing direction ofthe housing/cover connection corresponds to the opening direction of theelement/cover connection, the element/cover connection can be unlockedautomatically on locking of the housing/cover connection, in so far assaid element/cover connection was previously locked. Hereby inparticular also a resource-conserving filter element exchange is to bemade possible.

From DE 10 2008 011 616 A1 a filter housing is known, which extendsalong a longitudinal axis and comprises two housing parts which aredetachably connected to one another. The connection of the two housingparts is detachable by rotation of the one housing part in a rotationdirection about the longitudinal axis relative to the other housingpart. Furthermore, an anti-rotations means for the two housing partswith respect to one another is provided, with an actuating lever, whichtogether with its lever axis is embodied in one piece and in amaterially integral manner with a wall of one of the two housing parts.Hereby, it is to be possible to mount or respectively dismantle thecover more easily.

In fuel- or respectively lubricant filter systems, in particular in thecase of large annular filter elements, such as for example in utilityvehicle filters, intensive friction forces occur between sealing ringsand sealing surfaces. By the expanding of the sealing rings during theoperation of the filter systems, these forces can be additionallyintensified. Hereby, during servicing, it can occur that theconventional holding forces of a clip connection between a cover and theannular filter element are not sufficient to also draw the latter outfrom the filter housing pot on loosening of the cover, so that itremains therein and must be removed therefrom laboriously.

SUMMARY

The present invention is therefore concerned with the problem ofindicating for a filter device of the generic type an improved or atleast an alternative embodiment, which in particular is easier tomaintain.

This problem solved according to the invention by the subject of theindependent claims. Advantageous embodiments are the subject of thedependent claims.

The present invention is based on the general idea of using a newconnection between a cover of a housing of a filter device and anannular filter element, which can transfer sufficient force duringservicing in order to be able to draw the annular filter element outfrom a filter housing pot and namely even if seals have expanded after alengthy operation and therefore increased removal forces are necessary.The filter device according to the invention has here a housing with afilter housing pot and a cover that can be screwed onto it, and anannular filter element, arranged in the housing, with a pin protrudingaxially from a lower disc for closing a run-off channel. The annularfilter element itself is connected to the cover via a first thread,wherein this first thread comprises a dome protruding centrally andaxially from an upper end disc of the annular filter element, with anouter thread interrupted by free passages, and hollow cylindrical springelements protruding axially on the cover, wherein on the spring elementsrespectively an inner thread portion is arranged respectively, designedto complement the outer thread. Each of these inner thread portionsextends here over a longer circumferential portion than one of the freepassages. Furthermore, the first thread is designed running counter to asecond thread arranged between the filter housing pot and the cover.With the thread configured according to the invention between the coverand the annular filter element, it is particularly easy to also mount orrespectively dismantle comparatively large annular filter elements, forexample in utility vehicles. On mounting, firstly here the annularfilter element is screwed in the cover, wherein this screwing ispossible with few rotational movements owing to the free passagesprovided in the outer thread of the annular filter element.Subsequently, the thus pre-mounted assembly can be screwed to the filterhousing pot, wherein for example a carrier geometry, arranged on a faceside of the dome, cooperates with a counter-carrier geometry on thecover side, such that the annular filter element during mounting of thecover, i.e. during screwing onto the filter housing pot, co-rotatesuntil the pin engages into the run-off channel. Starting from thismoment in time, the annular filter element is prevented from a furtherrotational movement and is pressed by the cover further downward intothe filter housing pot, until the second thread is completely screwedtightly and the pin engages completely and in a sealed manner into therun-off channel.

A dismantling of the cover together with the annular filter elementtakes place now such that the cover is unscrewed from the filter housingpot in the usual manner, wherein the annular filter element remainsinitially with its pin in the run-off channel and thereby does notco-rotate with the cover. Through the thread pitches, configured in awedge-shaped manner, both on the inner thread portion and also on theouter thread the annular filter element can now be drawn up owing to theoppositely directed inclination of the first thread relative to thesecond thread and thereby the pin can be drawn out from the run-offchannel.

Alternatively, of course also firstly the annular filter element can beinserted into the filter housing pot and subsequently the cover can bescrewed on. Here, likewise, the inner thread portions slide over theirsliding inclinations along the sliding inclinations of the outer thread,wherein a correct positioning of the pin relative to the run-off channelis now not achieved exclusively via the carrier geometry, but inaddition also via the inner thread portions of the spring elements.After the engaging of the pin into the run-off channel, through theconfiguration of the first thread according to the invention and inparticular of the spring elements protruding axially on the cover andarranged in a hollow cylindrical manner, it can be achieved that thelatter slide over the thread pitches of the outer thread on the annularfilter element, for which both on the outer thread and also on the innerthread portions of the spring elements sliding inclinations arearranged. Via these sliding inclinations/sliding surfaces, therespective inner thread portion of a spring element is moved until it isguided over the outer thread and snaps back inwards again elasticallyand thereby engages behind the outer thread on the dome of the annularfilter element.

It is particularly advantageous in the filter device according to theinvention that a mounting of the annular filter element in the filterdevice irrespective of the two alternatives is possible comparativelysimply and without greater expenditure of force. In the same way, adismantling of the annular filter element also proves to be simple,because the inner thread portions are able to transfer high forces tothe annular filter element in axial direction.

In a further advantageous embodiment of the solution according to theinvention, a total of eight spring elements are provided withrespectively one inner thread portion. Additionally or alternatively,the outer thread can have a total of six free passages. This specialembodiment of the outer thread and of the inner thread portion makespossible both a reliable and simple mounting and also, in the same way,a reliable and simple dismantling, in which in any case it can beensured that even in the case of expanded seals and thereby high holdingforces between the annular filter element and the filter housing pot,the annular filter element can be drawn out reliably from the filterhousing pot.

Expediently, the dome and the outer thread with its free passages areformed in one piece with the upper end disc. Here, it suggests itself toform the upper end disc together with dome and with the outer thread asa favourably priced plastic injection-moulded part, wherein of course inthe same manner also the lower end disc together with the pin can beformed as a favourably priced, one-piece plastic injection-moulded part.

The present invention is further based on the general idea of indicatingan annular filter element for such a previously described filter device,with a pin protruding axially from a lower end disc for closing arun-off channel and with a dome protruding axially centrally from anupper end disc with an outer thread interrupted by free passages.Through the special configuration of the inner thread portion and of theouter thread, a type of key/lock principle can also be realized, whichenforces the use of an authorized annular filter element, whereby inparticular a long-term first class filter performance can be guaranteed.

Further important features and advantages of the invention will emergefrom the subclaims, from the drawings and from the associated figuredescription with the aid of the drawings.

It shall be understood that the features mentioned above and to beexplained further below are able to be used not only in the respectivelyindicated combination, but also in other combinations or in isolation,without departing from the scope of the present invention.

Preferred example embodiments of the invention are illustrated in thedrawings and are explained further in the following description, whereinthe same reference numbers refer to identical or similar or functionallyidentical components.

BRIEF DESCRIPTION OF THE DRAWINGS

There are shown here, respectively diagrammatically,

FIG. 1 a view, partially in section, onto a filter device according tothe invention,

FIG. 2 a detail illustration from the region of a first thread,

FIG. 3 a view, likewise partially in section, of the filter device,

FIG. 4 a sectional illustration through the filter device in the regionof the first thread,

FIG. 5 on the left a view onto the first thread, on the right anillustration as on the left, but without annular filter element.

DETAILED DESCRIPTION

According to FIG. 1, a filter device 1 according to the invention, whichcan be constructed for example as a fuel- or as a lubricant filter in autility vehicle, has a filter housing pot 2 and a cover 3 which can bescrewed onto it (cf. also FIGS. 3 and 4), and an annular filter element4 arranged therein. The annular filter element 4 has an upper end disc 5and a lower end disc 6, wherein on the lower end disc 6 a watercollecting space 7 with an axially protruding pin 8 is arranged. Thelatter engages, when the filter device 1 is installed, into a run-offchannel 9 and closes the latter. According to the invention, the annularfilter element 4 is connected to the cover 3 via a first thread 10. Thefirst thread 10 is formed here by a dome 11 protruding centrally axiallyfrom the upper end disc 5 of the annular filter element 4 (cf. alsoFIGS. 2 to 5) with an outer thread 13, interrupted by free passages 12,and spring elements 14 protruding axially on the cover 3 and arrangedhollow-cylindrically, on which respectively an inner thread portion 15designed to complement the outer thread 13 is arranged. Here, each ofthe inner thread portions 15 extends over a longer circumferentialportion, i.e. over a longer circular segment portion, than a freepassage 12. Furthermore, the first thread 10 is designed running counterto a second thread 16 arranged between the filter housing pot 2 and thecover 3.

Observing both the outer thread 13 and also the associated inner threadportions 15, it can be seen that these are formed in a wedge-shapedmanner and respectively have a sliding surface 17, the significance ofwhich will be described further below. Owing to their at least slightradial elasticity, the spring elements 14 also make possible aninserting of the annular filter element 4 into the cover 3, at which theouter thread 13 moves over its sliding surface 17 the associated innerthread portion 15 outwards over its sliding surface 17, until the outerthread 13 engages behind the inner thread portion 15 and thereby thespring element 14 springs back radially inwards.

Here, at least two spring elements 14 and two free passages 12 areprovided. Preferably, a total of eight spring elements 14 are providedwith respectively an inner thread portion 15. Furthermore, the outerthread 13 has a total of six free passages 12. This offers theparticular advantage of making possible a simple mounting of the annularfilter element 4 in the filter device 1 and likewise also a reliabledismantling thereof.

The dome 11 and the outer thread 13 with its free passages 12 arepreferably formed here in one piece with the upper end disc 5, so thatthe latter can be produced as a plastic injection-moulded part in asingle manufacturing step in a simple manner as regards production andat a favourable cost. The first thread 10 is formed here preferably as aleft-hand thread, whereas the second thread 16 is then formed as aright-hand thread. Of course, a reverse embodiment is also conceivable.

Observing FIGS. 4 and 5, it can be seen that on a face side 18 of thedome 11 a carrier geometry 19 is arranged, which cooperates with acounter-carrier geometry 20 arranged on the cover 3 such that theannular filter element 4, on mounting of the cover 3, is co-rotateduntil the pin 8 engages into the run-off channel 9.

The mounting of the annular filter element 4 in the filter device 1 isgenerally configured as follows:

Firstly, the annular filter element 4 with its dome 11 can be screwed tothe cover 3 via the first thread 3, which owing to the free passages 12is possible with little expenditure of force and small rotationalmovements. Subsequently, the assembly which is pre-mounted in such amanner is inserted into the filter housing pot 2 and in so doing thecover 3 is screwed to the filter housing pot 2. As the first thread 10is designed running counter to the second thread 16, firstly aco-rotating of the annular filter element 4 takes place via the carriergeometry 19 and the counter-carrier geometry 20, until said annularfilter element engages with its pin 8 into the run-off channel 9.Starting from this moment in time, only the cover 3 is twisted into thefinal position. With a further screwing-on of the cover 3, the innerthread portions 15 can now slide over their sliding surfaces 17 of theouter thread 13 and can be moved radially outwards until the innerthread portions 15 engage behind the outer thread 13 again and thespring elements 14 spring back radially inwards.

Alternatively to this mounting process, of course also firstly theannular filter element 4 can be positioned in the filter housing pot 2and the cover 3 can only be subsequently screwed on. The correctposition of the pin 8 is achieved here not only via the carrier geometry19 but also via the geometry of the inner thread portions 15 and of theouter thread 13. With a further screwing on of the cover 3, the innerthread portions 15 can now slide over their sliding surfaces 17 of theouter thread 13 and be moved radially outwards, until the inner threadportions 15 engage behind the outer thread 13 again and the springelements 14 spring back radially inwards.

A dismantling of the annular filter element 4 from the filter device 1takes place by a simple unscrewing of the cover 3, wherein through thefirst thread 11 oppositely directed to the second thread 16 a drawing upof the annular filter element 4 and thereby a drawing out of the pin 8from the run-off channel 9 is brought about. Through the wedge-shapedgeometry both of the outer thread 13 and also of the inner threadportions 15, these two thread portions interlock and enable a reliableand nevertheless low-force drawing out of the annular filter element 4.

In order to be able to guarantee a long-lasting and high-quality filterperformance, the carrier geometry 19 and the counter-carrier geometry 20and also the outer thread 13 and the inner thread portions 15 of thespring elements 14 cooperate in the manner of a key/lock principle, sothat exclusively annular filter elements 4 with matching carriergeometry 19 and matching outer thread 13 can be connected to the cover 3and inserted into the filter device 1.

The invention claimed is:
 1. A filter device comprising: a filterhousing with a filter housing pot and a cover screwable onto the filterhousing pot; and an annular filter element arranged in the filterhousing, the annular filter element having an axially protruding pin forclosing a run-off channel; wherein the annular filter element isconnected to the cover via a first thread; wherein the first thread hasa dome protruding centrally and axially from an upper end disc of theannular filter element, with an outer thread interrupted by freepassages, and hollow cylindrical spring elements which protrude axiallyfrom the cover and on which an inner thread portion designed tocomplement the outer thread is arranged; wherein each inner threadportion extends over a longer circumferential portion than one of thefree passages; wherein the first thread is designed running counter to asecond thread arranged between the filter housing pot and the cover. 2.The filter device according to claim 1, wherein a total of eight springelements are provided with the inner thread portion.
 3. The filterdevice according to claim 1, wherein the outer thread has a total of sixfree passages.
 4. The filter device according to claim 1, wherein thedome and the outer thread with the free passages are formed in one piecewith the upper end disc.
 5. The filter device according to claim 1,wherein the first thread is formed as a left-hand thread and the secondthread as a right-hand thread.
 6. The filter device according to claim1, wherein on a face side of the dome a carrier geometry is arranged,which cooperates with a counter-carrier geometry on a cover side suchthat the annular filter element on mounting of the cover co-rotatesuntil the pin engages into the run-off channel.
 7. The filter deviceaccording to claim 1, wherein the filter device is constructed as one ofa fuel filter or a lubricant filter.
 8. An annular filter element for afilter device, comprising: an axially and eccentrically protruding pin;a dome protruding centrally and axially from an upper end disc with anouter thread interrupted by free passages.
 9. The annular filter elementaccording to claim 8, wherein the outer thread has at least two freepassages.
 10. The annular filter element according to claim 8, whereinthe dome and the outer thread with the free passages are formed in onepiece with the upper end disc.
 11. The annular filter element accordingto claim 9, wherein the outer thread has six free passages.
 12. Thefilter device according to claim 2, wherein the dome and the outerthread with the free passages are formed in one piece with the upper enddisc.
 13. The filter device according to claim 2, wherein the firstthread is formed as a left-hand thread and the second thread as aright-hand thread.
 14. The filter device according to claim 2, whereinon a face side of the dome a carrier geometry is arranged, whichcooperates with a counter-carrier geometry on a cover side such that theannular filter element on mounting of the cover co-rotates until the pinengages into the run-off channel.
 15. The filter device according toclaim 2, wherein the filter device is constructed as one of a fuelfilter or a lubricant filter.
 16. A filter device comprising: a filterhousing with a filter housing pot and a cover screwable onto the filterhousing pot; and an annular filter element arranged in the filterhousing, the annular filter element having an axially protruding pin forclosing a run-off channel; wherein the annular filter element isconnected to the cover via a first thread; wherein the first thread hasa dome protruding centrally and axially from an upper end disc of theannular filter element, with an outer thread interrupted by freepassages, and hollow cylindrical spring elements which protrude axiallyfrom the cover and on which an inner thread portion designed tocomplement the outer thread is arranged; wherein each inner threadportion extends over a longer circumferential portion than one of thefree passages; wherein the first thread is designed running counter to asecond thread arranged between the filter housing pot and the cover;wherein on a face side of the dome a carrier geometry is arranged, whichcooperates with a counter-carrier geometry on a cover side such that theannular filter element on mounting of the cover co-rotates until the pinengages into the run-off channel.
 17. The filter device according toclaim 16, wherein a total of eight spring elements are provided with theinner thread portion.
 18. The filter device according to claim 16,wherein the outer thread has a total of six free passages.
 19. Thefilter device according to claim 16, wherein the dome and the outerthread with the free passages are formed in one piece with the upper enddisc.
 20. The filter device according to claim 16, wherein the firstthread is formed as a left-hand thread and the second thread as aright-hand thread.